In a Long Term Evolution (LTE) system, a smallest unit of a resource is a resource element (RE). An RE is a symbol in a time domain and is a subcarrier in a frequency domain. A resource block (RB) is a smallest unit for resource scheduling. An RB is a timeslot in the time domain and is 12 contiguous subcarriers in the frequency domain.
A heterogeneous network refers to a network including nodes with different powers. These nodes may include a macro base station (macro evolved NodeB, hereinafter referred to as macro eNB), a micro cell (Pico Cell), a home evolved NodeB (HeNB), a relay, and the like. Compared with a homogeneous network (that is, a network including macro base stations having a same transmit power), when heterogeneous network technologies are used, because an additional new serving node is introduced, an effect of cell splitting can be achieved, thereby improving system performance. However, in the heterogeneous network, because a low-power serving node is introduced, an interference scenario is different from that in the homogeneous network. If working frequencies of an interfering cell and an interfered-with cell are the same, a time division multiplexing (TDM) solution and a frequency division multiplexing (FDM) solution may be used to solve a problem of interference on a data channel.
In the TDM solution, an interfering cell (for example, a macro cell) transmits signals of different power levels in different subframes. In this way, because a low transmit power is allocated to some subframes or no data is sent in some subframes, these subframes are referred to as almost blank subframes (ABS). Therefore, in these subframes, an interfered-with cell (for example, a Pico Cell) schedules a user equipment (UE) in these subframes, where the user equipment is easily affected by the interfering cell, so as to reduce interference from the interfering cell (for example, the macro cell) to the UE in these subframes, thereby solving a problem of strong interference to the interfered-with cell (for example, the Pico Cell).
Because an ABS is introduced, interference features in different subframes may differ greatly. If measured subframes are not distinguished, it may cause wrong scheduling by a base station (evolved NodeB, hereinafter referred to as eNB). Therefore, the prior art introduces two subframe sets CCSI,0, and CCSI,1, which are used to measure resource-restricted channel state information (CSI) and provide feedback. Specifically, subframes having a same interference feature are grouped into one set, and a network may configure UE to perform channel quality indication (CQI) measurement and reporting in each of the two subframe sets. In this way, the eNB can schedule the UE in a more targeted manner according to measurement results that are reported by the UE and acquired in different measurement sets. However, similarly, the foregoing two measurement sets correspond to a same node connected to the UE.
In the prior art, a multiple stream aggregation (MSA) scenario is introduced in an LTE system, that is, one UE may be connected to multiple stations at the same time and receives service data from the multiple stations. The UE in the MSA scenario has a feature of dual connectivity, that is, one UE may be connected to multiple stations at the same time. For example, one UE may be connected to a macro base station and a micro base station (Pico eNB, hereinafter referred to as PeNB), where the macro base station and the PeNB may have a same frequency or may have different frequencies. Coverage areas of PeNBs are small, and if a UE moves fast, the UE easily moves from a coverage area of one PeNB into a coverage area of another PeNB frequently, causing frequent handovers of the UE. Dual connectivity enables a UE to keep connected to a macro base station and a PeNB at the same time, where the macro base station provides the UE with a service for content related to mobility management and a real-time service, while the PeNB provides only a data service. In this way, dual connectivity can avoid frequent handovers.
In the MSA scenario, for a UE on an edge of a coverage area of a Pico, a macro cell may serve the UE in a specific subframe (for example, a non-ABS of the macro cell) of the macro cell, while the Pico Cell serves the UE in a specific subframe (for example, a subframe corresponding to an ABS of the macro cell) of the Pico Cell. In this case, CSI measurement performed by the UE on the macro cell and the Pico Cell needs to correspond to a resource that can serve the UE, so that reference can be made to corresponding channel state information to satisfy a requirement for proper scheduling.
That is, in the MSA scenario, at least two transmission points provide data transmission services for a UE, and each serving point serves the UE in only a specific radio resource set.
In the prior art, there may be two sets on a node, and after a UE is notified of a configuration condition of the two sets, the UE performs CSI measurement on each of the two sets and provides feedback, so that a base station can perform data scheduling for the UE on a suitable resource.
However, in the prior art, only in a case in which two restricted measurement sets are from a same transmission point and only two restricted CSI measurement sets are configured on a node, a UE can be notified of a restricted measurement resource, but in an MSA scenario, when one or more specific radio resource sets are configured on each transmission point for the UE, the UE cannot be notified of the foregoing configured specific radio resource set.